YOM KIPPUR: FORGIVEN FOR THE SIN OF THE GOLDEN CALF

The Midrash Seder Olam Rabbah 6 gives the chronology of the period between receiving the Torah at Mount Sinai and the following tenth day of Tishrei (Yom Kippur).

On the sixth day of Sivan the Ten commandments were given. On the seventh day of Sivan, Moses / Moshe ascended the mountain. Moshe remained on the mountain for forty days and forty nights.